EF1 tornado in Plaquemines Parish, Louisiana

A strong EF-1 tornado occurred over predominantly inaccessible marshes of Plaquemines Parish. High resolution satellite imagery aided in the identification of damage to marsh vegetation after the tornado caused significant damage to a newly rebuilt camp on an island between Oaks Bayou and Lake Laurier. No ground survey could be performed to review the entirety of the structure's construction. Thus, the damage and wind speed estimates were based on one before and just a few after damage photos emailed to NWS from the home owner. The camp was not Fortified certified, nor was any information given in regards to licensed engineer involvement in its construction. However, many straps can be seen on the camp along floor joists, wall to roof hurricane straps and tension rods in the walls connecting the roof to the floor. All of that points towards a well built home generally speaking. The before photo shows what appears to be a wrap around porch. 3 of the roof overhangs were around 5 feet wide and the 4th overhand was 10 to 20 feet wide. The very wide overhangs were likely the biggest contributing factor to entire roof uplift that occurred. The significant vertical component of winds close to the core of a tornado would have enhanced the wind loads even further on these large overhands for an elevated structure relative to a typical straight line wind event. 4 inch by 4 inch posts connected the roof overhangs with 1/2 inch galvanized bolts. When the roof was uplifted, it took with it all the 4x4 posts as well as the camp staircases. Once the roof was gone, its unsurprising that most of the exterior walls collapse regardless of having tension rods. Other absent important information includes whether doors or windows were impact rated. In consultation with a structural engineer based on the limited information and pictures available, the rating will be 110 MPH unless additional information can be received. Additional damage to the marsh was identified near Hermitage Road with a few trees apparently damaged as well as the tornado weakened and dissipated before reaching the Mississippi River. Satellite analysis may add additional damage points to the southwest of the damaged track so this track may be extended in future updates.

The first of 2 surface lows moved into the Red River Valley which drew a stalled frontal boundary over the northern Gulf northward as a warm front in the morning hours. Doing so brought fast warming trend along with a definite moisture increase. Instability in that warm sector was further enhanced by daytime heating. Every severe weather parameter was moderate to high with this system, so there is not surprising to have widespread reports of wind, hail, and multiple tornadoes.